static void Main(string[] args)
{
Lion lion = new Lion();
Mammal one = lion; //부모타입으로 형변환
one.Move();
Human human = new Human();
Mammal two = human;
two.Move();
}
static void Main(string[] args)
{
Mammal one = new Mammal();
one.Move();
Lion lion = new Lion();
lion.Move();
Whale whale = new Whale();
whale.Move();
Human human = new Human();
human.Move();
Lion lion2 = new Lion();
Mammal one2 = lion2; //부모타입으로 형변환
one2.Move();
}